(i) Field of the Invention
The present invention relates to a differential gear for permitting a difference in speed of rotation between right and left driving wheels of a motor vehicle for instance.
(ii) Description of the Related Art
A differential gear for the motor vehicle is a unit for permitting a difference in speed of rotation between right and left driving wheels which may occur when the motor vehicle is moving in a curve, or a difference in speed of rotation between front and rear driving wheels of a motor vehicle with four-wheel drive. A typical arrangement of the differential gear is such that a pinion gear intervenes between a pair of bevel gears coupled to output shafts, and that when an external rotational force is applied to the pinion gear shaft, the pinion gear rotates on its own axis at the time of occurrence of a differential motion so as to permit a difference in speed of rotation between the output shafts.
By the way, when the motor vehicle turns along a curve, a difference in speed of rotation occurs between the inner wheel and the outer wheel is permitted by the above-described differential gear, the difference in speed of rotation being caused attendantly as a result of a frictional force between the wheels and the surface of a road. It is thus possible to enhance the turning performance or the high-speed stability by positively generating the difference in speed of rotation between the driving wheels. If, for instance, the left-hand wheel is rotated faster than the ordinary rotational speed upon a rightward turning, then the handling operation for turning will be facilitated. Also, when the motor vehicle is subjected to a strong lateral wind upon a straight movement, if the wheel on the downwind side is rotated faster than the wheel on the opposite side, the automobile can be prevented from being transversely urged without any extreme handling operation. Accordingly, the realization of such a unit with a simple structure would be very effective in enhancing the performance of the motor vehicles.